This is a very old version and you can not use the api of a newer version with that version of course. Just update your sytm to 3.0.4.6. Btw, if you want to keep your system secure and prevent data loss, then you should update regularily.

If not: how to update to the 3.0.4.6 version with 100% prevention of loosing data...? (the server is on production state and no data should be lost)

Click to expand...

Just follow the normal update procedure as described in the release note:

The soap connection is the same then the one that you use to access the ispconfig interface in the browser. So if you are able to login to ispconfig at all, then you must be able to access the soap interface as well, soap is just a different subfolder ( /remote/ ) of the same base URL.